Post on 15-Mar-2020
transcript
JSW STEEL LTD, DOLVI
Innovative Approach at JSW Steel, Dolvi Works with
Emphasis on SIP Process.
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Making Steel is our Profession …
Generating Smile is our Passion…
Sinter Plant 2.8 MTPA
Blast Furnace 2 MTPA
Sponge Iron Plant 1.6 MTPA
SMS (Con-Arc) 4.0 MTPA
Thin Slab Caster 3.3 MTPA
Hot Strip Mill 3.3 MTPA
Iron Ore Iron Ore & Fluxes
NG
DRI
Hot Metal
LCP 1200 TPD
Cal. Lime
Liquid Steel
Slab
Pellet Plant 4 MTPA
Coke Oven 1 MTPA
Coal
BF
Ga
s
55 MW Power Plant
Blast Furnace 3.5 MTPA
Sinter Plant 2.24 MTPA
SMS (Con-Arc) 5.0 MTPA
Billet Caster 1.5 MTPA
Billet
Bar Mill 1.5 MTPA
Bars
5 MTPA CONFIGURATION
53.5 MW power plant leading to a net saving of 0.32 Gcal/tcs
Pulverised coal injection in Blast Furnace
6MW gas expansion turbine at blast Furnace
20% replacement of NG at gas based DRI plant with in-house generated COG
Usage of 100% low grade pellet at DRI plant
In plant Initiatives towards Energy and Cost saving
Case Study
Sponge Iron Plant
(Coke oven gas usage in Sponge Iron Plant)
Sponge Iron Plant: Overview
Technology MIDREX, Gas based
Commissioned -1994
Original capacity-1.0 MTPA
World’s first mega module DRI plant.
After De bottlenecking in 2005 capacity 1.6 MTPA
Designed to use only Natural gas as a source of
hydrocarbons for Production of Hydrogen & Carbon
mono-oxide by catalytic reforming.
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TOP GAS
SCRUBBER
TOP GAS
COMPRESSOR
PROCESS GAS
STAGE1 STAGE2
NG
FLUE
GAS
EJECTOR STACK
SEAL GAS COMPRESSOR
2 1 SEAL GAS
EJECTOR
FAN
COMPRESSOR
COOLING GAS
COOLING GAS
SCRUBBER
HEAT RECOVERY
REFORMER
REDUCING
GAS
COOLING
ZONE
REDUCING
ZONE
FLUE GAS
IRON OXIDE
COMBUSTION AIR
FEED GAS
MAIN AIR BLOWER
R.G.
MIXER
LIME
COATING NG + COG OXYGEN
NG +
COG
NG
SIP Process Flow Diagram
Pellet Lump
COG 11,500 NM3/Hr
DRI
1. Surplus Coke oven gas availability after commissioning of coke oven battery in Feb’14.
2. Coke oven gas is having useful components like H2, CO & Methane with small amount
of impurities like Benzene, H2S, Tar, CnHm etc.
3. Coke oven gas use in SIP was not possible because it has detrimental effect on
reformer catalyst.
4. Other Plants in complex have no more margin to utilize available coke oven gas thus
was bound to be vented.
Element COG Composition
CH4 23 – 27 %
CmHn 2 – 4 %
H2 56 – 60 %
CO 5 – 8 %
CO2 1.5 – 3 %
O2 0.3 – 0.8 %
N2 3 -7 %
Benxene 33 gm/NM3
HCN 0.28 gm/NM3
Project background
1. A series of brain storming session were taken to access how to use coke oven Gas.
2. Way out found to use coke oven gas in Furnace. By using Furnace heat and DRI as
catalyst to reform coke oven gas.
3. Next task as to implement it in house without much investment and least modifications.
4. Scheme developed for coke oven gas injection in Furnace.
5. Looked for available equipment in-house.
6. A spare lobe type compressor for seal gas service was available , decided to use the
same with modifications.
Break Through steps
Hurdles with Counter Measure
Sr Hurdle Counter Measures Start date
End date
1 Impurities content in COG (like CnHm, Benzene, Tar etc)
COG composition @ 10000 NM3/Hr was checked for it’s suitability to use in DRI Plant. Found no major change in gas quality.
18-11-13 20-11-13
2 Low Pressure COG supply
Spare Seal gas compressors modified to make it suitable for Coke oven gas.
25-11-13 02-05-14
3 Civil Foundation of 3rd Seal gas compressor
Old 3rd Seal gas compressor foundation was modified to install single motor driven two stage Cold COG compressors to boost pressure from 0.10 bar g to @ 2 bar g.
20-05-14 04-04-14
4 COG Supply tapping
Tapping of 400 mm size was taken from COG main header going to Tunnel Furnace
05-04-14 10-04-14
5 Piping, Instrumentation & DCS modification
Developed In-house piping scheme & Process interlocks system.
02-04-14 25-04-14
6 DCS Graphic, PLC interlocks & Process calculations
Used available spare IOs of existing DCS system 01-05-14 15-05-14
7 Seal legs & Drain water
New Seal legs of 30 mtr deep drilled in sump for drains of Compressor, Dampners & aftercooler
20-05-14 26-05-14
8 Excess moisture, solid contaminants & steady pressure
Spare Propane knock out pot installed at Compressor suction to remove free moisture & solid contaminants in COG
25-05-14 30-05-14
9 Blockage of Compressor lobes due to scaling
Replaced Process water with Soft water for compressor spary water.
20-06-14 15-07-14
Process monitoring Before & After COG Addition
Date Unit 12-Aug-14 8 to12 Nov 14
Before COG addition After Cold COG addition
Production Mt 3411 3367
Production rate TPH 142 140
Process Gas Flow KNM3/Hr 142 140.0
Process NG Flow KNM3/Hr 23.3 20.3
NG to Furnace KNM3/Hr 15.2 12.2
Reformed gas Temp DegC 940 958
Reformed gas Methane DegC 0.82 0.52
Process Gas CnHm % Nil Nil
Bustle Gas Temperature DegC 930 930
Oxygen Flow SM3 1127 1692
Oxygen Consumption NN3/Mt 7.94 12.1
Total NG KSM3/Day 924 781
COG Flow KSM3/Day 0.0 279
NM3/Hr 0.0 11500
COG Temp DegC 0 38
Sp Heat Gcal/Mt 2.392 2.358
Power kWh/Mt 89.4 94.1
Reduction in NG consumption KSM3/Day 137
Reduction in NG w.r.t COG % 49
Product Quality
Metallization % 94.1 94.1
Carbon % 1.72 1.76
Financial Benefits
Use of 1 NM3 of COG results in saving of Rs 10.40 Annual savings of 98 Crores
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First plant in the world to use COG for DRI Production. This was the real morale booster to SIP
Injection of 11500 NM3/Hr Cold COG at 35-40 Deg.C with the help of lobe type compressor resulting in saving of 5750 NM3/Hr Natural gas.
Reduction in energy consumption after using Coke oven gas in DRI plant @ 1.5 to
2.0%.
Reduction in CO2 emission by 0.50% by using coke oven gas in DRI process as compared to using coke oven gas as a fuel in other facilities.
Reduced dependency on expensive, imported natural gas by @ 45 million standard
cubic meters per annum
Cold COG to Furnace
Benefits after COG Usage in DRI Plant
Energy Reduction of using COG in place NG
Coke oven gas is available in house.
Reduction in Energy to transport LNG from source to destination in India by ship.
Saving in Energy to gasify LNG to RLNG at unloading station in India.
Reduction in Energy to compress the RLNG to 75 ~ 80 bar for transportation to end user.
Reduction in Fuel consumption to reform CH4 into Hydrogen & Carbon Monoxide required for reduction of Iron oxide.
Saving in Foreign currency to buy costly RLNG.
Way Forward:
• Implementation of the same scheme in SIP across JSW group.
•100 % Replacement Natural gas from present 20% by using Coke oven gas.
Thank You...